weight scales

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PaulDoug

PaulDoug

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I'm slowing trying to get set up to try casting. Just curious what scales people use to weigh out their PR mixture, or what else do you use?
 
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PR doesn't need to be weighed. You simply fill your mold with the material. Most of which is the resin with just a few drops of the catalyst. So you are more interested in volume.


I've not used Alumilite, but I think it's a 1 to 1 mixture of a and b. If that's the case, again you just need two equal volumes that combine to be the volume you need to fill the mold. weight isn't needed.


Simple way to figure out what you need. 1)fill your mold with water. 2) pour the water into a disposable plastic cup and mark the level. That's the volume you are looking for.
 
Some people use scales to weigh the pigments and catalyst and such. And as pointed out, if you use Alumilite you will need scales.

I pour with PR, so I also only concern myself with volume. I use a silicone muffin pan cut up into 6 individual cups. Each cup is right at 5 ounces, and this gives me a 30 ounce our with up to 6 colors. I use schedule40 PVC molds. They are about 7 inches long. I can get at least 3 or 4 pours before it is time to get new PVC. 1/2" molds take about 1 1/2 ounces of resin. 3/4" molds take about 2 1/2 ounces.

I measure the catalyst (MEKP) by the drop... 4 per ounce of resin is what i like. I measure my pigment (Mica) by the pinky nail on a popcicle stick method.

hope that helps
 
Monty said:
Alumilite is 1:1 by weight, not volume. I picked up a small scale from Harbor Freight for under $10.
Click to expand...

yeah, just went and looked at the pics on their site and you can see the two parts are different volumes in the bottles for the Clear. The White can go either way, volume or weight, it looks like.
 
I measure by volume. 4 drop of catalyst per ounce. If you are doing small molds figure the volume. I am using the resin saver molds for sierra pens. I filled one cavity with water and poured into a jigger glass and scratched the outside to mark the volume. Any chemical supply will sell you a small plastic measuring cup marked in milliliters or ounces for a couple of dollars they are very accurate. I had problems with plastic cups melting so I went to glasses, when done pouring a quick wipe with a paper towel followed by a wipe with acetone wet towel keeps the glass clean for the next pour. I also had a fire in a toaster oven (cup melted) so I now use a small crock-pot to preheat my resin.
Mark
 
As said, Alumilite needs to be done by weight, equal parts of A and B. I use a regular old dial postal scale. It does not have to be super precise but needs to be close. The best way to figure out how much you need is to figure your mold volume but multiplying length x height x width. Then multiply that times .554 and that is how much you need. To me, that is better than putting water in your mold since Alumilite HATES ANY water.
 
I work by weight (grams) using a cheap Harbor Freight digital scale.

This way I can use any suitable container without worrying about having it marked for fluid oz, in^3, etc. Just put the mixing cup on the scale, tare it, then add enough resin to do what I want.

Of course, if I was doing worthless wood I wouldn't be able to calculate the needed volume or weight- but weighing the resin would still ensure either I had the proper ratio of A to B using alumilite, or amount of MEKP using PR.
 
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